This disclosure relates to a deep red phosphor and a method of manufacturing the same.
A red phosphor is used as a visible-light emitting material for various displays or lamps such as light emitting diodes (LED) liquid crystal displays (LCD), and cold cathode fluorescence lamps (CCFL).
In general, white LEDs are formed of a combination of red, green and blue LEDs. However, these white LEDs embrace problems, such as high manufacturing cost and bulkiness, due to the complex driving circuits associated thereto.
In order to solve these problems, the white LEDs use an ultraviolet (IV) LED as its excitation light source. Further, the white LED is manufactured by combining a red phosphor, a green phosphor and a blue phosphor to thereby obtain nearly natural white light. Typically, this white LED uses UV light having a long wavelength of about 400 nm as its excitation light source. Accordingly, these phosphors used for fabricating the white LED need to have a high efficiency of visible light-emitting when excited by the UV excitation light source having such a long wavelength.
To obtain these white LEDs, many kinds of red phosphors, green phosphors and blue phosphors have been developed. However, brightness of the red phosphor is lower than that of the green phosphor or the blue phosphor. For this reason, the white LED is to contain a larger amount of red phosphor, relative to the blue phosphor or the green phosphor.
3.5MgO.0.5MgF2.GeO2:Mn and K5Eu(WO4)6.25 has been used as the red phosphor for long-wavelength UV LEDs. However, these materials exhibit relatively low brightness and emission efficiency when excited by an excitation light source of 400 nm or greater.
In particular, a high quality display device such as full HD TVs for displaying an abundant sense of color has been increasingly demanded. As such, the demand for the red phosphor, which is one of important factors to high-quality color display, has been increased. Further, the light-emitting efficiency of the red phosphor need be improved, especially in case of a deep red phosphor capable of displaying a deep red color.